The present invention relates to batteries, including fuel cells and re-chargeable fuel cells, for use in powering electrical devices.
Batteries such as fuel cells are useful for the direct conversion of chemical energy into electrical energy. Fuel cells are typically made up of three chambers separated by two porous electrodes. A fuel chamber serves to introduce a fuel, typically hydrogen gas, which can be generated in situ by xe2x80x9creformingxe2x80x9d hydrocarbons such as methane with steam, so that the hydrogen contacts H2O at the first electrode, where, when a circuit is formed between the electrodes, a reaction producing electrons and hydronium (H3O+) ions is catalyzed.
2H2O+H22H3O++2exe2x88x92xe2x80x83xe2x80x83(1)
A central chamber can comprise an electrolyte. The central chamber acts to convey hydronium ions from the first electrode to the second electrode. The second electrode provides an interface with a recipient molecule, typically oxygen, found in the third chamber. The recipient molecule receives the electrons conveyed by the circuit.
2H3O++1/2O2+2exe2x88x923H2Oxe2x80x83xe2x80x83(2)
The electrolyte element of the fuel cell can be, for example, a conductive polymer material such as a hydrated polymer containing sulfonic acid groups on perfluoroethylene side chains on a perfluoroethylene backbone such as Nafion(trademark) (du Pont de Nemours, Wilmington, Del.) or like polymers available from Dow Chemical Co., Midland, Mich. Other electrolytes include alkaline solutions (such as 35 wt %, 50 wt % or 85 wt % KOH), acid solutions (such as concentrated phosphoric acid), molten electrolytes (such as molten metal carbonate), and solid electrolytes (such as solid oxides such as yttria (Y2O3)-stabilized zirconia (ZrO2)). Liquid electrolytes are often retained in a porous matrix. Such fuel cells are described, for example, in xe2x80x9cFuel Cells,xe2x80x9d Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Vol. 11, pp. 1098-1121.
These types of fuel cells typically operate at temperatures from about 80xc2x0 C. to about 1,000xc2x0 C. The shortcomings of the technology include short operational lifetimes due to catalyst poisoning from contaminants, high initial costs, and the practical restrictions on devices that operate at relatively high to extremely high temperatures.
The present invention provides a fuel cell technology that employs molecules used in biological processes to create fuel cells that operate at moderate temperatures and without the presence of harsh chemicals maintained at high temperatures, which can lead to corrosion of the cell components. While the fuel used in the fuel cells of the invention are more complex, they are readily available and suitably priced for a number of applications, such as power supplies for mobile computing or telephone devices. It is anticipated that fuel cells of the invention can be configured such that a 300 cc cell has a capacity of as much as 80 Wxc2x7hxe2x80x94and thus can have more capacity than a comparably sized battery for a laptop computerxe2x80x94and that such cells could have still greater capacity. Thus, it is believed that the fuel cells of the invention can be used to increase capacity, and/or decrease size and/or weight. Moreover, the compact, inert energy sources of the invention can be used to provide short duration electrical output. Since the materials retained within the fuel cells are non-corrosive and typically not otherwise hazardous, it is practical to recharge the fuel cells with fuel, with the recharging done by the consumer or through a service such as a mail order service.
Moreover, in certain aspects, the invention provides fuel cells that use active transport of protons to increase sustainable efficiency. Fuel cells of the invention can also be electrically re-charged.
In one aspect, the invention provides a fuel cell comprising a first compartment, a second compartment and a barrier separating the first and second compartments, wherein the barrier comprises a proton transporting moiety.
In another aspect, the invention provides a fuel cell a first compartment; a second compartment; a barrier separating the first compartment from the second compartment; a first electrode; a second electrode; a redox enzyme in the first compartment in communication with the first electrode to receive electrons therefrom, the redox enzyme incorporated in a lipid composition; an electron carrier in the first compartment in chemical communication with the redox enzyme; and an electron receiving composition in the second compartment in chemical communication with the second electrode, wherein, in operation, an electrical current flows along a conductive pathway formed between the first electrode and the second electrode.